This invention broadly relates to an improved method of separating bitumin from bituminous sands at temperatures sufficiently low to prevent thermal decomposition of the hydrocarbon content. The invention further relates to a method of preparing organic acids such as humic acids and asphaltic acids and the recovery thereof as a byproduct.
A number of large deposits of bituminous sands are known to the oil and mining industry such as the Athabaskan or Canadian tar sands and the bituminous sands found in the Vinta basin of Utah and Colorado and especially in the vicinity of Vernal, Utah. These deposits contain many billions of tons of bituminous sands and it has been long recognized that the deposits would be very valuable provided an economical method of separating the bitumin from the sand was available. A variety of methods have been proposed heretofore. In accordance with one method, the bituminous sands are retorted at high temperatures which result in the destructive distillation of the bituminous content and valuable hydrocarbons contained therein are thermally decomposed and can not be recovered for sale. Thus, the retorting or destructive distillation method has not been successful to date from the economic standpoint.
Low temperature methods of recovering the bitumin content have also been proposed heretofore. However, they have not been entirely successful as there was no known way of economically separating the bitumin which adheres tightly to the sand particles. As a result, solvents have been used to dissolve the bitumin content and leave the sand particles behind as a residue. The solvent is used to treat the entire volume of the bituminous sand and it is costly as a large amount of solvent is lost in the sand residue and the dissolved bitumin must be recovered from the solution by distillation. Attempts to use nonsolvents such as water have not been successful heretofore as only a small percentage of the bitumin content could be separated thereby rendering the process uneconomic as well as inefficient.
The present invention provides an inexpensive and entirely satisfactory method of recovering bitumin from bituminous sands at temperatures far below the decomposition temperature of the valuable hydrocarbon content. The method employs a unique and highly effective technique for breaking the bonds between the bitumin and the sand particles, thereby allowing the bitumin to be easily separated from the sand. The separated bitumin may be further treated in accordance with prior art processes to produce synthetic petroleum, or to produce products for use in the chemical industry, the rubber industry, road building and the like.
It is an object of the present invention to provide a novel method of economically separating bitumin from bituminous sand which employs temperatures far below the decomposition temperature of the valuable hydrocarbon content.
It is a further object to provide a novel method of treating bituminous sands whereby the bonds which cause the bitumin to adhere tightly to the sand particles may be broken and the surface properties and/or characteristics of the sand particles and/or bitumin may be altered so that the bitumin may be easily separated from the sand.
It is a further object to provide a novel method wherein bituminous sands are intimately contacted with an aqueous medium containing a novel catalyst at temperatures below the decomposition temperature to separate a plurality of butumin fractions of increasing viscosity and/or molecular weight from the residual sand fraction.
It is a further object to prepare and recover valuable organic acids from bituminous sands.
Still other objects and advantages of the invention will be apparent to those skilled in the art upon reference to the following detailed description and the specific examples which are for purposes of illustration only.